This chapter takes issue with the dominant notion that political polarization can be understood as a process through which parties diverge on a single dimension of political conflict. Rather, I introduce the notion that affective political polarization intensifies when new issue dimensions are added. In a two-party system, the parties will appear to be moving further from the average voter, and further from one another, if they offer ever-more heterogeneous and incoherent bundles of platforms over time as new issues are politicized. In the United States, as a result, increasing hostility toward the out-party goes hand in hand with increased ambivalence about the in-party. Meanwhile, the parties become increasingly internally fractious. In a multiparty system, on the other hand, when new issues emerge, parties can position themselves throughout the multidimensional issue space. As a result, voters feel closer not only to their in-party but also to the average out-party. In this way, I suggest that multiparty systems can reduce overall levels of affective polarization.